Annotate PDF Online — Text, Highlight, Draw
Draw notes, highlights, pen strokes and shapes on PDF pages and save them
Runs in your browser · nothing is uploaded
Adds text, shapes, pen strokes and highlights on top of the pages and saves them. It does not edit or delete the text already in the PDF.
Drop the PDF to annotate here
Add one PDF (up to 100 MB). Adding another file replaces the current one. Files never leave your browser.
What it does
Circle what needs fixing in a report, highlight key clauses in a contract or leave notes on an assignment. Open a PDF, choose a page and draw with text, highlighter, pen, rectangle, ellipse, line or arrow tools, then save a new PDF with your marks. Nothing to install, and the file is not uploaded.
How to use
- Drop one PDF on the box or press Choose PDF.
- On the left, pick a tool, colour and line width; for text, type it and choose the size.
- Drag on the page to draw shapes and highlights, or draw freely with the pen. For text, click where it should go.
- With Select & move, drag marks to move them and drag the blue dot to resize. A selected text mark can be edited in the text box.
- Use Previous page / Next page for other pages, then press Save PDF with marks.
How it works
- Coordinates: marks are stored relative to the page as displayed; on saving, one transformation per page (rotation and visible box) maps them into PDF space. The original content is wrapped in q/Q so its graphics state cannot interfere.
- Highlighter: 35 % colour with Multiply blending, so the text underneath shows through.
- Pen: strokes are saved as vector lines and stay sharp when zoomed.
- Clean files: objects nothing refers to are dropped on saving.
- Libraries: pdf-lib (MIT) draws; the preview is rendered with PDF.js (Apache-2.0).
Examples
| Goal | Steps |
|---|---|
| Mark a sentence to fix | Yellow highlighter over the sentence |
| Leave a review comment | Text tool, red, 14 pt, “check this number” |
| Point at part of a figure | Arrow tool, drag |
| Emphasize the signature box | Rectangle, blue, 2 pt |
To place a signature image, use Sign PDF; to lock form fields and comments into the page, use Flatten PDF.
FAQ
Can I edit the existing text in the PDF?
No. This tool draws on top of the pages; it does not change or delete the text already there. Covering text with a white box leaves the text underneath in the file, so remove sensitive information from the source document instead.
Can other PDF apps edit my marks later?
Marks are drawn into the page content, not saved as PDF comment annotations. They look the same in every viewer and print, but apps such as Acrobat cannot list or delete them as comments.
Does it work with the keyboard?
Yes. Pick a tool and press "Add in the centre", Tab to the mark, then use the arrow keys to move it (Shift for larger steps), Alt+arrows to resize, +/- to grow or shrink and Delete to remove it. With the pen tool, focus the editing area, draw with the arrow keys and press Enter. Ctrl+Z undoes and Ctrl+Y redoes.
Which font is used for text?
Latin text uses Helvetica, a PDF standard font, so nothing is embedded. Text with Korean embeds a subset of Noto Sans KR (SIL Open Font License). Emoji and Han characters are not in that font; they are left out and listed.
Do marks land correctly on rotated pages?
Yes. Each page's rotation and visible area (CropBox) are taken into account, so marks appear upright where you placed them.
Related tools
Sign PDF
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Flatten PDF
Flatten PDF form values and annotations into the page, or remove comments and links in bulk
Fill PDF Form
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